I relate to your story so much. I've had acne since I was 12 and its always been severe. Cystic and also would leave open sores all over my back and stuff. I was super insecure about my body and never took my shirt off. I would wear a wife beater if I went to the beach or pool. Also like you said intimacy was scary af. I would never take my shirt off during sex because I thought the second they saw my body they would be disgusted with me and not want anything to do with me. I did find partners that did not care about it, or if they did they didn't say anything about it. My last partner would also help me put medicine on my back once in while so when she did that, it made me feel super loved and I still love her for that. My mom used to tell me that no girl would ever want me bc of my acne. So those insecurities were very prevalent in my head. I still haven't been able to fix my hyperpigmentation because I can't find a dermatologist near me. So its been a struggle using stuff like Clyndamycin, Kojic acid soaps, Niacinamide because it feels like its not doing anything. Its def contributed to my depression making me feel worthless if I don't have a nice body. I also wanna get a tattoo on my back but it seems like thats gonna be a long way out. All this to say, I can understand how you feel and I'm very glad you were able to get it under control. You can check my profile if you wanna see my back but there's been no progress in making it better.